Neurons are cells that possess polarity by themselves, that is, they process directionality. Namely, neurons have multiple dendrites and a single axon, receive information from other neurons at their dendrites, and integrate the inputs within their cell body to convert them into an action potential that transmits over the axon from the cell body to the synaptic terminal. Neurotransmitters are then released from the synaptic terminus to transmit information to a target cell. This phenomenon is the basis for higher-order life activities such as memory, learning and exercise in higher organisms. Most of polarity formation in a neuron and the molecular mechanisms of maintenance, however, remain unknown (for research regarding polarity formation, see for example Dotti, C. G., Sullivan, C. A., Banker, G. A. (1988) The Establishment of Polarity by Hippocampal Neurons in Culture. J. Neurosci. 8, 1454-1468).
Deciphering the molecular mechanisms of polarity formation in a neuron would elucidate the molecular mechanisms of axon formation and elongation during the developmental stage, and also those of the formation of neural networks. The formation of polarity is one aspect of axon formation in a neuron. When the molecules involved in the polarity formation is identified, the molecules could be employed to form or elongate nerve axons. There is also a possibility that those same molecules could be utilized in the development of a novel nerve regeneration technology, such as could be used in the development of medical therapies for the regeneration of severed or degenerated nerve axons.
The development of such therapies is of great importance. For example, there are no effective drug therapies for axonal regeneration of the central and peripheral nerve damage caused by stroke or trauma, and currently the primary medical approach for such damage is rehabilitation to recover nerve function. In particular, once impaired, the axons of central nerves cannot be regenerated, often confining the patient to a wheel-chair for life. This makes the disorder a high burden on the patients, their families, and society.